docs: def _build_config(self):
          '''
          Build the config of the napalm syslog parser.
          '''
          if not self.config_dict:
              if not self.config_path:
                  # No custom config path requested
                  # Read the native config files
                  self.config_path = os.path.join(
                      os.path.dirname(os.path.realpath(__file__)),
                      'config'
                  )
              log.info('Reading the configuration from %s', self.config_path)
              self.config_dict = self._load_config(self.config_path)
          if not self.extension_config_dict and\
             self.extension_config_path and\
             os.path.normpath(self.extension_config_path) != os.path.normpath(self.config_path):  # same path?
              # When extension config is not sent as dict
              # But `extension_config_path` is specified
              log.info('Reading extension configuration from %s', self.extension_config_path)
              self.extension_config_dict = self._load_config(self.extension_config_path)
          if self.extension_config_dict:
              napalm_logs.utils.dictupdate(self.config_dict, self.extension_config_dict)